Heat a large pot with the oil. Add the onion, garlic, celery, carrot. Stirring about 4 min.
Add the broccoli, potatoes, water, broth. Cover the pot and bring to the boil. Reduce the heat to low and simmer the soup for 5-6 minutes or until the veggies are fork tender.
Blend the soup until puree. Add the cashew, blend again. Add the salt, pepper. Let the soup sit for about 5 minutes. Add more water if needed.
Serve with ciabatta, parsley, cashew, and/or broccoli florets.